For sending
First the receiver needs "trained" by sending 01010101.....
Then send in this example "9" then the next character is used to do something.
Code:
TRAIN	VAR BYTE

TRAIN=$55
SEROUT PORTC.4,T2400,[TRAIN,TRAIN,TRAIN,TRAIN,TRAIN,9,3]
For receiving
Code:
net 	VAR WORD
SERIN PORTC.4,T2400,[9],net
IF net = 3 THEN DO SOMETHING
This is the basics, when you get this working try for some type of encoding.